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Stem Cell Debate Drives Alternatives

Scientists Search for Way Around Ethical Controversy

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Plucking Grapes

Meanwhile, researchers at a Massachusetts biotech firm called Advanced Cell
Technologies (ACT) have shown they can extract stem cells from early embryos
without killing them. The technique has been used for a decade to perform early
genetic testing during fertility treatments.

The extraction takes place when a fertilized embryo is about two-and-a-half
days old and consists of just eight cells.

"You are able to pluck out one of those cells just as you would pluck
out a grape from a bunch of grapes," Robert Lanza, ACT's vice president of
research, told the Washington forum.

Lanza's company showed that an extracted cell can be grown into pleuripotent
stem cell line, and that the remaining embryo is just as viable as a normal one
-- at least in mice.

This method was promoted by conservatives in Congress who opposed a repeal
of the federal limits on embryonic stem cell research.

It also provides a way around the narrow supply of fertility clinic embryos
that prospective parents would clear for use in research.

The method is essentially a hedge for Lanza, who favors still-controversial
cloning methods to create a supply of stem cells from early embryos.

Preventing Implantation

Last year in the journal Nature, scientists at the Whitehead
Institute for Biomedical Research in Cambridge, Mass., published results from
an experiment in which they removed a gene in mice that allows an embryo to
implant in the mother's uterus.

Without that gene, any embryos produced through cloning (in this case, mouse
cloning) could not implant and hence could not be born.

That created a buzz in religious circles but did not settle the
controversy.

Some Catholic authorities, including William Levada, the Archbishop of San
Francisco, endorsed the procedure by stating that embryos without the ability
to implant in a womb are not "true embryos."

But some anti-abortion groups, including the American Life League, rejected
the method, saying it would "create and then kill human embryos."

The controversy around the procedure is unlikely to end any time soon, Lanza
says.